Recently, high speed operation of semiconductor devices is being demanded together with high functionality of the electronic devices which use these semiconductor devices which leads to an increase in the amount of heat being generated when operating a semiconductor element. Because operation errors occur due to an increase in the temperature of a semiconductor element when operating the semiconductor element, operation reliability decreases and therefore, a means for dissipating the heat generated when operating the semiconductor element is required.
A cross sectional view of a conventional semiconductor device which is not mounted with a heat dissipation component is shown in FIG. 1.
In the conventional semiconductor device 10, a semiconductor element 3 is mounted on a substrate 1 with an adhesive 2 and the semiconductor element 3 is connected to the substrate using a bonding wire 4 made from a material such as Au or Cu etc. The periphery of the semiconductor element 3 is molded by a mold component 5 having epoxy etc. as its main raw material. In the semiconductor device 10, heat which is generated when the semiconductor element 3 operates is thermally conducted to the mold component 5 on the semiconductor element 3 and dissipates by thermal conduction to the air from the surface of the mold component 5.
In addition, in FIG. 2 or FIG. 3, a method is shown for improving the heat dissipation of semiconductor devices 20, 30 by mounting a heat dissipation component 7, 31 comprised from metal etc. on the surface of the mold component 5, and increasing the thermal conductivity of the mold component by about 3 [W/mK]. Heat resistance of a semiconductor device decreases by about 10-15% in a semiconductor device which includes this heat dissipation component compared to a semiconductor device which does not include a heat dissipation component.
In Patent Document 1 (Japan Laid Open Patent 2007-305761) an example is shown whereby a heat dissipation plate is attached to a semiconductor element by a conductivity paste and an upper surface side of an edge part of the heat dissipation plate is supported by a heat dissipation plate push part. In this example, heat generated from the semiconductor element is conducted to the heat dissipation plate by the conductivity paste and dissipates from a thermal conduction means such as a heat sink arranged on the heat dissipation plate to the air.
In addition, in Patent Document 2 (Japan Laid Open Patent 2001-210761) an example of shown whereby a sheet shaped heat dissipation plate is arranged by an adhesive on the semiconductor element so as to cover the semiconductor element. In this example, heat generated from the semiconductor element is conducted to the heat dissipation plate by the adhesive and dissipates by thermal conduction to the air from the heat dissipation plate.
However, environments in which a heat sink is not or can not be mounted on a semiconductor device are increasing due to the increasing thinness and small scale of recent electronic devices, and a means for further reducing the temperature of a semiconductor element, that is, reducing the heat resistance of a semiconductor device in such environments, is being demanded. As such a means, in a semiconductor device mounted with heat dissipation components 7, 31 comprised of metal etc., on the surface of a mold component so as to be exposed to the air as in the conventional semiconductor device shown in FIG. 2 or FIG. 3, the mold component 5 with a thickness of tens of [μm] to hundreds of [μm] is sandwiched between heat dissipation components 7, 31 and the semiconductor element 3, the thermal conductivity of the mold component 5 is about 0.5-3 [W/mK] which is a low thermal conductivity compared to metal etc., therefore heat resistance is large and the heat generated from the semiconductor element 3 does not diffuse sufficiently within the mold component 5. In addition, in the conventional semiconductor devices 20, 30 mounted with heat dissipation components 7, 31 which are exposed to the air, because the heat dissipation area up to the heat dissipation components 7, 31 which allow heat generated from the surface of the semiconductor element 3 to dissipate is limited, sufficient heat dissipation effects can not be obtained from the surface of the semiconductor device.
Therefore, heat is not sufficiently dissipated from the surface of the semiconductor devices 20, 30 having this conventional structure, and is limited as a means for reducing the temperature of the semiconductor element 3.
The present invention aims to effectively diffuse heat generated when a semiconductor element operates within a mold component, improve heat dissipation of a semiconductor device and reduce heat resistance.